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LRS Bianchi type-I models have been studied in the cosmological theory based on Lyra's geometry. A new class of exact solutions has been obtained by considering a time dependent displacement field for variable deceleration parameter models…

General Relativity and Quantum Cosmology · Physics 2010-05-28 Anirudh Pradhan , D. S. Chauhan

A Bianchi type-I cosmological model in the presence of a magnetic flux along a cosmological string is considered. The first objective of this study is to investigate Einstein equations using a tractable assumption usually accepted in the…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Victor Rikhvitsky , Bijan Saha , Mihai Visinescu

Bianchi type V perfect fluid cosmological models are investigated with cosmological term $\Lambda$ varying with time. Using a generation technique (Camci {\it et al.}, 2001), it is shown that the Einstein's field equations are solvable for…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Anirudh Pradhan , A. K. Yadav , L. Yadav

The study of a self-consistent system of interacting spinor and scalar fields within the scope of a Bianchi type I (BI) gravitational field in presence of a viscous fluid and $\Lambda$ term has been carried out. The system of equations…

General Relativity and Quantum Cosmology · Physics 2015-05-01 Bijan Saha , Victor Rikhvitsky

We investigate a corner of the Bianchi models that has not received much attention: "extended FLRW models" (eFLRW) defined as a cosmological model with underlying anisotropic Bianchi geometry that nevertheless expands isotropically and can…

General Relativity and Quantum Cosmology · Physics 2020-02-21 Mikjel Thorsrud , Ben D. Normann , Thiago S. Pereira

We investigate some new similarity inhomogeneous solutions of anisotropic dark energy and perfect fluid in Bianchi type-I space-time. Three different equation of state parameters along the spatial directions are introduced to quantify the…

General Relativity and Quantum Cosmology · Physics 2018-04-12 Ahmad T Ali , Anil Kumar Yadav , Abdulah K Alzahrani

In this article, we propose an anisotropic Bianchi-I type cosmological model in non-conservative Unimodular Gravity ($\mathrm{NUG}$). We show that simply using the Bianchi-I type metric does not resolve a striking characteristic of the…

General Relativity and Quantum Cosmology · Physics 2025-11-26 Marcelo H. Alvarenga , Júlio C. Fabris

In this article we perform the Wheeler-DeWitt quantization for Bianchi type $I$ anisotropic cosmological model in the presence of a scalar field minimally coupled to the Einstein-Hilbert gravity theory. We also consider the cosmological…

General Relativity and Quantum Cosmology · Physics 2019-08-14 Saumya Ghosh , Sunandan Gangopadhyay , Prasanta K. Panigrahi

We analyze the effective dynamics of a polymer quantized homogeneous and anisotropic Bianchi-I universe coupled to a polymer quantized scalar field. We use a pressureless dust field as an internal clock, and work with the gravitational…

General Relativity and Quantum Cosmology · Physics 2025-09-30 Aleena Zulfiqar , Syed Moeez Hassan

We consider a self-consistent system of Bianchi type-I (BI) gravitational field and a binary mixture of perfect fluid and dark energy given by a cosmological constant. The perfect fluid is chosen to be the one obeying either the usual…

General Relativity and Quantum Cosmology · Physics 2015-05-01 Bijan Saha

Self-consistent system of spinor, scalar and BI gravitational fields is considered. Exact solutions to the field equations in terms of volume scale of the BI metric are obtained. Einstein field equations in account of the cosmological…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Bijan Saha , Todor Boyadjiev

Some features of the Bianchi type-I universes in the presence of a fluid that wields an anisotropic equation of state (EoS) parameter are discussed in the context of general relativity. The models that exhibit de Sitter volumetric expansion…

General Relativity and Quantum Cosmology · Physics 2010-03-02 Ozgur Akarsu , Can B. Kilinc

The behaviour of the flat anisotropic model of the Universe with a scalar field is explored within the framework of quantum cosmology. The principal moment of the account of an anisotropy is the presence either negative potential barrier or…

General Relativity and Quantum Cosmology · Physics 2015-06-25 V. N. Folomeev , V. Ts. Gurovich

We investigate Bianchi I cosmological model in the theory of a dilatonM field coupled to gravity through a Gauss-Bonnet term. Two type ofM cosmological singularity are distinguished. The former is analogous toM the Einstein gravity…

General Relativity and Quantum Cosmology · Physics 2009-10-31 S. Alexeyev , A. Toporensky , V. Ustiansky

We investigate diagonal Bianchi-I spacetimes in the presence of viscous fluids by using the shear and the anisotropic pressure components as the basic variables, where the viscosity is driven by the (second-order) causal thermodynamics. A…

General Relativity and Quantum Cosmology · Physics 2017-02-13 Eduardo Bittencourt , Leandro G. Gomes , Renato Klippert

A complete qualitative study of the dynamics of string cosmologies is presented for the class of isotopic curvature universes. These models are of Bianchi types I, V and IX and reduce to the general class of Friedmann-Robertson-Walker…

High Energy Physics - Theory · Physics 2009-10-31 Andrew P. Billyard , Alan A. Coley , James E. Lidsey

The stability of isotropic cosmological solutions in the Bianchi I model is considered. We prove that the stability of isotropic solutions in the Bianchi I metric for a positive Hubble parameter follows from their stability in the…

High Energy Physics - Theory · Physics 2009-11-05 Irina Ya. Aref'eva , Nikolay V. Bulatov , Liudmila V. Joukovskaya , Sergey Yu. Vernov

Motivated by anomalies in cosmic microwave background observations, we investigate the implications of $f(Q, T)$ gravity in Bianchi type-I spacetime, aiming to characterize the universe's spatially homogeneous and anisotropic properties. By…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-30 A. Zhadyranova , M. Koussour , V. Zhumabekova , O. Donmez , S. Muminov , J. Rayimbaev

A spatially homogeneous and anisotropic Bianchi Type I universe has been studied with {\omega} <-1 without Big Smash. It is demonstrated that if cosmic dark energy behaves like a fluid with equation of state p = {\omega}{\rho} (p and {\rho}…

General Relativity and Quantum Cosmology · Physics 2011-08-04 Anil Kumar Yadav

The present study deals with LRS Bianchi type I cosmological model representing massive string. The energy-momentum tensor for such string as formulated by Letelier (1983) is used to construct massive string cosmological models for which we…

General Relativity and Quantum Cosmology · Physics 2011-12-22 Anil Kumar Yadav